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b44cd882 TG |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright (C) 2013 Intel Corporation. All rights reserved. | |
7 | Copyright (C) 2014 Tom Gundersen | |
8 | ||
9 | systemd is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU Lesser General Public License as published by | |
11 | the Free Software Foundation; either version 2.1 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | systemd is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | Lesser General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU Lesser General Public License | |
20 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
21 | ***/ | |
22 | ||
ff734080 | 23 | #include <sys/ioctl.h> |
be077570 | 24 | #include <netinet/if_ether.h> |
ff734080 | 25 | |
87322b3a TG |
26 | #include "siphash24.h" |
27 | ||
b44cd882 TG |
28 | #include "sd-dhcp-server.h" |
29 | #include "dhcp-server-internal.h" | |
ff734080 | 30 | #include "dhcp-internal.h" |
b44cd882 | 31 | |
4dc35568 TG |
32 | #define DHCP_DEFAULT_LEASE_TIME 60 |
33 | ||
2dead812 TG |
34 | int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, struct in_addr *address, |
35 | size_t size) { | |
36 | assert_return(server, -EINVAL); | |
37 | assert_return(address, -EINVAL); | |
38 | assert_return(address->s_addr, -EINVAL); | |
39 | assert_return(size, -EINVAL); | |
40 | assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY); | |
41 | assert_return(!server->pool_size, -EBUSY); | |
87322b3a TG |
42 | assert_return(!server->bound_leases, -EBUSY); |
43 | ||
44 | server->bound_leases = new0(DHCPLease*, size); | |
45 | if (!server->bound_leases) | |
46 | return -ENOMEM; | |
2dead812 TG |
47 | |
48 | server->pool_start = address->s_addr; | |
49 | server->pool_size = size; | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
20af7091 TG |
54 | int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address) { |
55 | assert_return(server, -EINVAL); | |
56 | assert_return(address, -EINVAL); | |
57 | assert_return(address->s_addr, -EINVAL); | |
58 | assert_return(server->address == htobe32(INADDR_ANY), -EBUSY); | |
59 | ||
60 | server->address = address->s_addr; | |
61 | ||
62 | return 0; | |
63 | } | |
64 | ||
b44cd882 TG |
65 | sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) { |
66 | if (server) | |
67 | assert_se(REFCNT_INC(server->n_ref) >= 2); | |
68 | ||
69 | return server; | |
70 | } | |
71 | ||
87322b3a TG |
72 | unsigned long client_id_hash_func(const void *p, const uint8_t hash_key[HASH_KEY_SIZE]) { |
73 | uint64_t u; | |
74 | const DHCPClientId *id = p; | |
75 | ||
76 | assert(id); | |
77 | assert(id->length); | |
78 | assert(id->data); | |
79 | ||
80 | siphash24((uint8_t*) &u, id->data, id->length, hash_key); | |
81 | ||
82 | return (unsigned long) u; | |
83 | } | |
84 | ||
85 | int client_id_compare_func(const void *_a, const void *_b) { | |
86 | const DHCPClientId *a, *b; | |
87 | ||
88 | a = _a; | |
89 | b = _b; | |
90 | ||
91 | assert(!a->length || a->data); | |
92 | assert(!b->length || b->data); | |
93 | ||
94 | if (a->length != b->length) | |
95 | return a->length < b->length ? -1 : 1; | |
96 | ||
97 | return memcmp(a->data, b->data, a->length); | |
98 | } | |
99 | ||
100 | static void dhcp_lease_free(DHCPLease *lease) { | |
101 | if (!lease) | |
102 | return; | |
103 | ||
104 | free(lease->client_id.data); | |
105 | free(lease); | |
106 | } | |
107 | ||
108 | DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPLease*, dhcp_lease_free); | |
109 | #define _cleanup_dhcp_lease_free_ _cleanup_(dhcp_lease_freep) | |
110 | ||
b44cd882 TG |
111 | sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) { |
112 | if (server && REFCNT_DEC(server->n_ref) <= 0) { | |
87322b3a TG |
113 | DHCPLease *lease; |
114 | Iterator i; | |
115 | ||
b44cd882 TG |
116 | log_dhcp_server(server, "UNREF"); |
117 | ||
ff734080 TG |
118 | sd_dhcp_server_stop(server); |
119 | ||
b44cd882 | 120 | sd_event_unref(server->event); |
87322b3a TG |
121 | |
122 | HASHMAP_FOREACH(lease, server->leases_by_client_id, i) { | |
123 | hashmap_remove(server->leases_by_client_id, lease); | |
124 | dhcp_lease_free(lease); | |
125 | } | |
126 | ||
127 | hashmap_free(server->leases_by_client_id); | |
128 | free(server->bound_leases); | |
b44cd882 TG |
129 | free(server); |
130 | } | |
131 | ||
132 | return NULL; | |
133 | } | |
134 | ||
3a864fe4 | 135 | int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) { |
b44cd882 TG |
136 | _cleanup_dhcp_server_unref_ sd_dhcp_server *server = NULL; |
137 | ||
138 | assert_return(ret, -EINVAL); | |
3a864fe4 | 139 | assert_return(ifindex > 0, -EINVAL); |
b44cd882 TG |
140 | |
141 | server = new0(sd_dhcp_server, 1); | |
142 | if (!server) | |
143 | return -ENOMEM; | |
144 | ||
145 | server->n_ref = REFCNT_INIT; | |
8de4a226 | 146 | server->fd_raw = -1; |
ff734080 | 147 | server->fd = -1; |
20af7091 | 148 | server->address = htobe32(INADDR_ANY); |
3a864fe4 | 149 | server->index = ifindex; |
87322b3a | 150 | server->leases_by_client_id = hashmap_new(client_id_hash_func, client_id_compare_func); |
b44cd882 TG |
151 | |
152 | *ret = server; | |
153 | server = NULL; | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, int priority) { | |
159 | int r; | |
160 | ||
161 | assert_return(server, -EINVAL); | |
162 | assert_return(!server->event, -EBUSY); | |
163 | ||
164 | if (event) | |
165 | server->event = sd_event_ref(event); | |
166 | else { | |
167 | r = sd_event_default(&server->event); | |
168 | if (r < 0) | |
169 | return r; | |
170 | } | |
171 | ||
172 | server->event_priority = priority; | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
177 | int sd_dhcp_server_detach_event(sd_dhcp_server *server) { | |
178 | assert_return(server, -EINVAL); | |
179 | ||
180 | server->event = sd_event_unref(server->event); | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) { | |
186 | assert_return(server, NULL); | |
187 | ||
188 | return server->event; | |
189 | } | |
ff734080 TG |
190 | |
191 | int sd_dhcp_server_stop(sd_dhcp_server *server) { | |
192 | assert_return(server, -EINVAL); | |
193 | ||
194 | server->receive_message = | |
195 | sd_event_source_unref(server->receive_message); | |
196 | ||
8de4a226 | 197 | server->fd_raw = safe_close(server->fd_raw); |
ff734080 TG |
198 | server->fd = safe_close(server->fd); |
199 | ||
200 | log_dhcp_server(server, "STOPPED"); | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
969b009d TG |
205 | static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, DHCPPacket *packet, |
206 | size_t len) { | |
207 | union sockaddr_union link = { | |
208 | .ll.sll_family = AF_PACKET, | |
209 | .ll.sll_protocol = htons(ETH_P_IP), | |
210 | .ll.sll_ifindex = server->index, | |
211 | .ll.sll_halen = ETH_ALEN, | |
212 | }; | |
213 | int r; | |
214 | ||
215 | assert(server); | |
216 | assert(server->index > 0); | |
217 | assert(server->address); | |
218 | assert(packet); | |
219 | assert(len > sizeof(DHCPPacket)); | |
220 | ||
221 | memcpy(&link.ll.sll_addr, &packet->dhcp.chaddr, ETH_ALEN); | |
222 | ||
223 | dhcp_packet_append_ip_headers(packet, server->address, DHCP_PORT_SERVER, | |
224 | packet->dhcp.yiaddr, DHCP_PORT_CLIENT, len); | |
225 | ||
226 | r = dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len); | |
227 | if (r < 0) | |
228 | return r; | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, | |
234 | DHCPMessage *message, size_t len) { | |
235 | union sockaddr_union dest = { | |
236 | .in.sin_family = AF_INET, | |
237 | .in.sin_port = htobe16(DHCP_PORT_CLIENT), | |
238 | .in.sin_addr.s_addr = destination, | |
239 | }; | |
240 | struct iovec iov = { | |
241 | .iov_base = message, | |
242 | .iov_len = len, | |
243 | }; | |
244 | uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))] = {}; | |
245 | struct msghdr msg = { | |
246 | .msg_name = &dest, | |
247 | .msg_namelen = sizeof(dest.in), | |
248 | .msg_iov = &iov, | |
249 | .msg_iovlen = 1, | |
250 | .msg_control = cmsgbuf, | |
251 | .msg_controllen = sizeof(cmsgbuf), | |
252 | }; | |
253 | struct cmsghdr *cmsg; | |
254 | struct in_pktinfo *pktinfo; | |
255 | int r; | |
256 | ||
257 | assert(server); | |
258 | assert(server->fd > 0); | |
259 | assert(message); | |
260 | assert(len > sizeof(DHCPMessage)); | |
261 | ||
262 | cmsg = CMSG_FIRSTHDR(&msg); | |
263 | assert(cmsg); | |
264 | ||
265 | cmsg->cmsg_level = IPPROTO_IP; | |
266 | cmsg->cmsg_type = IP_PKTINFO; | |
267 | cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
268 | ||
269 | /* we attach source interface and address info to the message | |
270 | rather than binding the socket. This will be mostly useful | |
271 | when we gain support for arbitrary number of server addresses | |
272 | */ | |
273 | pktinfo = (struct in_pktinfo*) CMSG_DATA(cmsg); | |
274 | assert(pktinfo); | |
275 | ||
276 | pktinfo->ipi_ifindex = server->index; | |
277 | pktinfo->ipi_spec_dst.s_addr = server->address; | |
278 | ||
279 | r = sendmsg(server->fd, &msg, 0); | |
280 | if (r < 0) | |
281 | return -errno; | |
282 | ||
283 | return 0; | |
284 | } | |
285 | ||
286 | static bool requested_broadcast(DHCPRequest *req) { | |
287 | assert(req); | |
288 | ||
289 | return req->message->flags & htobe16(0x8000); | |
290 | } | |
291 | ||
292 | int dhcp_server_send_packet(sd_dhcp_server *server, | |
293 | DHCPRequest *req, DHCPPacket *packet, | |
294 | int type, size_t optoffset) { | |
295 | be32_t destination = INADDR_ANY; | |
296 | int r; | |
297 | ||
298 | assert(server); | |
299 | assert(req); | |
300 | assert(req->max_optlen); | |
301 | assert(optoffset <= req->max_optlen); | |
302 | assert(packet); | |
303 | ||
304 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, | |
305 | DHCP_OPTION_SERVER_IDENTIFIER, | |
306 | 4, &server->address); | |
307 | if (r < 0) | |
308 | return r; | |
309 | ||
310 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, | |
311 | DHCP_OPTION_END, 0, NULL); | |
312 | if (r < 0) | |
313 | return r; | |
314 | ||
315 | /* RFC 2131 Section 4.1 | |
316 | ||
317 | If the ’giaddr’ field in a DHCP message from a client is non-zero, | |
318 | the server sends any return messages to the ’DHCP server’ port on the | |
319 | BOOTP relay agent whose address appears in ’giaddr’. If the ’giaddr’ | |
320 | field is zero and the ’ciaddr’ field is nonzero, then the server | |
321 | unicasts DHCPOFFER and DHCPACK messages to the address in ’ciaddr’. | |
322 | If ’giaddr’ is zero and ’ciaddr’ is zero, and the broadcast bit is | |
323 | set, then the server broadcasts DHCPOFFER and DHCPACK messages to | |
324 | 0xffffffff. If the broadcast bit is not set and ’giaddr’ is zero and | |
325 | ’ciaddr’ is zero, then the server unicasts DHCPOFFER and DHCPACK | |
326 | messages to the client’s hardware address and ’yiaddr’ address. In | |
327 | all cases, when ’giaddr’ is zero, the server broadcasts any DHCPNAK | |
328 | messages to 0xffffffff. | |
329 | ||
330 | Section 4.3.2 | |
331 | ||
332 | If ’giaddr’ is set in the DHCPREQUEST message, the client is on a | |
333 | different subnet. The server MUST set the broadcast bit in the | |
334 | DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the | |
335 | client, because the client may not have a correct network address | |
336 | or subnet mask, and the client may not be answering ARP requests. | |
337 | */ | |
338 | if (req->message->giaddr) { | |
339 | destination = req->message->giaddr; | |
340 | if (type == DHCP_NAK) | |
341 | packet->dhcp.flags = htobe16(0x8000); | |
342 | } else if (req->message->ciaddr && type != DHCP_NAK) | |
343 | destination = req->message->ciaddr; | |
344 | ||
345 | if (destination || requested_broadcast(req) || type == DHCP_NAK) | |
346 | return dhcp_server_send_udp(server, destination, &packet->dhcp, | |
347 | sizeof(DHCPMessage) + optoffset); | |
348 | else | |
349 | /* we cannot send UDP packet to specific MAC address when the address is | |
350 | not yet configured, so must fall back to raw packets */ | |
351 | return dhcp_server_send_unicast_raw(server, packet, | |
352 | sizeof(DHCPPacket) + optoffset); | |
353 | } | |
354 | ||
4dc35568 TG |
355 | static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret, |
356 | uint8_t type, size_t *_optoffset, DHCPRequest *req) { | |
357 | _cleanup_free_ DHCPPacket *packet = NULL; | |
358 | size_t optoffset; | |
359 | int r; | |
360 | ||
361 | assert(server); | |
362 | assert(ret); | |
363 | assert(_optoffset); | |
bd57b450 | 364 | assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK)); |
4dc35568 TG |
365 | |
366 | packet = malloc0(sizeof(DHCPPacket) + req->max_optlen); | |
367 | if (!packet) | |
368 | return -ENOMEM; | |
369 | ||
370 | r = dhcp_message_init(&packet->dhcp, BOOTREPLY, be32toh(req->message->xid), | |
371 | type, req->max_optlen, &optoffset); | |
372 | if (r < 0) | |
373 | return r; | |
374 | ||
375 | packet->dhcp.flags = req->message->flags; | |
376 | packet->dhcp.giaddr = req->message->giaddr; | |
377 | memcpy(&packet->dhcp.chaddr, &req->message->chaddr, ETH_ALEN); | |
378 | ||
379 | *_optoffset = optoffset; | |
380 | *ret = packet; | |
381 | packet = NULL; | |
382 | ||
383 | return 0; | |
384 | } | |
385 | ||
2dead812 | 386 | static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req, be32_t address) { |
4dc35568 TG |
387 | _cleanup_free_ DHCPPacket *packet = NULL; |
388 | size_t offset; | |
389 | be32_t lease_time; | |
390 | int r; | |
391 | ||
392 | r = server_message_init(server, &packet, DHCP_OFFER, &offset, req); | |
393 | if (r < 0) | |
394 | return r; | |
395 | ||
2dead812 | 396 | packet->dhcp.yiaddr = address; |
4dc35568 | 397 | |
c7d9ffe6 | 398 | lease_time = htobe32(req->lifetime); |
4dc35568 TG |
399 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
400 | DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, &lease_time); | |
401 | if (r < 0) | |
402 | return r; | |
403 | ||
404 | r = dhcp_server_send_packet(server, req, packet, DHCP_OFFER, offset); | |
405 | if (r < 0) | |
406 | return r; | |
407 | ||
408 | return 0; | |
409 | } | |
410 | ||
2dead812 TG |
411 | static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req, be32_t address) { |
412 | _cleanup_free_ DHCPPacket *packet = NULL; | |
413 | size_t offset; | |
414 | be32_t lease_time; | |
415 | int r; | |
416 | ||
417 | r = server_message_init(server, &packet, DHCP_ACK, &offset, req); | |
418 | if (r < 0) | |
419 | return r; | |
420 | ||
421 | packet->dhcp.yiaddr = address; | |
422 | ||
c7d9ffe6 | 423 | lease_time = htobe32(req->lifetime); |
2dead812 TG |
424 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
425 | DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, &lease_time); | |
426 | if (r < 0) | |
427 | return r; | |
428 | ||
429 | r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset); | |
430 | if (r < 0) | |
431 | return r; | |
432 | ||
433 | return 0; | |
434 | } | |
435 | ||
bd57b450 TG |
436 | static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) { |
437 | _cleanup_free_ DHCPPacket *packet = NULL; | |
438 | size_t offset; | |
439 | int r; | |
440 | ||
441 | r = server_message_init(server, &packet, DHCP_NAK, &offset, req); | |
442 | if (r < 0) | |
443 | return r; | |
444 | ||
445 | r = dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset); | |
446 | if (r < 0) | |
447 | return r; | |
448 | ||
449 | return 0; | |
450 | } | |
451 | ||
816e2e7a TG |
452 | static int parse_request(uint8_t code, uint8_t len, const uint8_t *option, |
453 | void *user_data) { | |
454 | DHCPRequest *req = user_data; | |
455 | ||
456 | assert(req); | |
457 | ||
458 | switch(code) { | |
c7d9ffe6 TG |
459 | case DHCP_OPTION_IP_ADDRESS_LEASE_TIME: |
460 | if (len == 4) | |
461 | req->lifetime = be32toh(*(be32_t*)option); | |
462 | ||
463 | break; | |
2dead812 TG |
464 | case DHCP_OPTION_REQUESTED_IP_ADDRESS: |
465 | if (len == 4) | |
466 | req->requested_ip = *(be32_t*)option; | |
467 | ||
468 | break; | |
816e2e7a TG |
469 | case DHCP_OPTION_SERVER_IDENTIFIER: |
470 | if (len == 4) | |
471 | req->server_id = *(be32_t*)option; | |
472 | ||
473 | break; | |
474 | case DHCP_OPTION_CLIENT_IDENTIFIER: | |
475 | if (len >= 2) { | |
476 | uint8_t *data; | |
477 | ||
478 | data = memdup(option, len); | |
479 | if (!data) | |
480 | return -ENOMEM; | |
481 | ||
482 | free(req->client_id.data); | |
483 | req->client_id.data = data; | |
484 | req->client_id.length = len; | |
485 | } | |
486 | ||
487 | break; | |
488 | case DHCP_OPTION_MAXIMUM_MESSAGE_SIZE: | |
489 | if (len == 2) | |
490 | req->max_optlen = be16toh(*(be16_t*)option) - | |
491 | - sizeof(DHCPPacket); | |
492 | ||
493 | break; | |
494 | } | |
495 | ||
496 | return 0; | |
497 | } | |
498 | ||
499 | static void dhcp_request_free(DHCPRequest *req) { | |
500 | if (!req) | |
501 | return; | |
502 | ||
503 | free(req->client_id.data); | |
504 | free(req); | |
505 | } | |
506 | ||
507 | DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPRequest*, dhcp_request_free); | |
508 | #define _cleanup_dhcp_request_free_ _cleanup_(dhcp_request_freep) | |
509 | ||
510 | static int ensure_sane_request(DHCPRequest *req, DHCPMessage *message) { | |
511 | assert(req); | |
512 | assert(message); | |
513 | ||
514 | req->message = message; | |
515 | ||
516 | /* set client id based on mac address if client did not send an explicit one */ | |
517 | if (!req->client_id.data) { | |
518 | uint8_t *data; | |
519 | ||
520 | data = new0(uint8_t, ETH_ALEN + 1); | |
521 | if (!data) | |
522 | return -ENOMEM; | |
523 | ||
524 | req->client_id.length = ETH_ALEN + 1; | |
525 | req->client_id.data = data; | |
526 | req->client_id.data[0] = 0x01; | |
527 | memcpy(&req->client_id.data[1], &message->chaddr, ETH_ALEN); | |
528 | } | |
529 | ||
530 | if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE) | |
531 | req->max_optlen = DHCP_MIN_OPTIONS_SIZE; | |
532 | ||
c7d9ffe6 TG |
533 | if (!req->lifetime) |
534 | req->lifetime = DHCP_DEFAULT_LEASE_TIME; | |
535 | ||
816e2e7a TG |
536 | return 0; |
537 | } | |
538 | ||
87322b3a TG |
539 | static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) { |
540 | assert(server); | |
541 | ||
542 | if (!server->pool_size) | |
543 | return -EINVAL; | |
544 | ||
545 | if (be32toh(requested_ip) < be32toh(server->pool_start) || | |
546 | be32toh(requested_ip) >= be32toh(server->pool_start) + | |
500792d8 | 547 | + server->pool_size) |
87322b3a TG |
548 | return -EINVAL; |
549 | ||
550 | return be32toh(requested_ip) - be32toh(server->pool_start); | |
551 | } | |
552 | ||
be077570 TG |
553 | int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, |
554 | size_t length) { | |
816e2e7a | 555 | _cleanup_dhcp_request_free_ DHCPRequest *req = NULL; |
87322b3a | 556 | DHCPLease *existing_lease; |
816e2e7a | 557 | int type, r; |
be077570 TG |
558 | |
559 | assert(server); | |
560 | assert(message); | |
561 | ||
562 | if (message->op != BOOTREQUEST || | |
563 | message->htype != ARPHRD_ETHER || | |
564 | message->hlen != ETHER_ADDR_LEN) | |
565 | return 0; | |
566 | ||
816e2e7a TG |
567 | req = new0(DHCPRequest, 1); |
568 | if (!req) | |
569 | return -ENOMEM; | |
570 | ||
571 | type = dhcp_option_parse(message, length, parse_request, req); | |
be077570 TG |
572 | if (type < 0) |
573 | return 0; | |
574 | ||
816e2e7a TG |
575 | r = ensure_sane_request(req, message); |
576 | if (r < 0) | |
577 | /* this only fails on critical errors */ | |
578 | return r; | |
579 | ||
87322b3a TG |
580 | existing_lease = hashmap_get(server->leases_by_client_id, &req->client_id); |
581 | ||
4dc35568 TG |
582 | switch(type) { |
583 | case DHCP_DISCOVER: | |
2dead812 | 584 | { |
87322b3a TG |
585 | be32_t address = INADDR_ANY; |
586 | unsigned i; | |
2dead812 | 587 | |
4dc35568 TG |
588 | log_dhcp_server(server, "DISCOVER (0x%x)", |
589 | be32toh(req->message->xid)); | |
590 | ||
2dead812 TG |
591 | if (!server->pool_size) |
592 | /* no pool allocated */ | |
593 | return 0; | |
594 | ||
87322b3a TG |
595 | /* for now pick a random free address from the pool */ |
596 | if (existing_lease) | |
597 | address = existing_lease->address; | |
598 | else { | |
599 | for (i = 0; i < server->pool_size; i++) { | |
600 | if (!server->bound_leases[server->next_offer]) { | |
601 | address = htobe32(be32toh(server->pool_start) + server->next_offer); | |
602 | break; | |
603 | } else | |
604 | server->next_offer = (server->next_offer + 1) % server->pool_size; | |
605 | } | |
606 | } | |
607 | ||
608 | if (address == INADDR_ANY) | |
609 | /* no free addresses left */ | |
610 | return 0; | |
2dead812 TG |
611 | |
612 | r = server_send_offer(server, req, address); | |
4dc35568 TG |
613 | if (r < 0) { |
614 | /* this only fails on critical errors */ | |
615 | log_dhcp_server(server, "could not send offer: %s", | |
616 | strerror(-r)); | |
617 | return r; | |
618 | } else { | |
619 | log_dhcp_server(server, "OFFER (0x%x)", | |
620 | be32toh(req->message->xid)); | |
621 | return DHCP_OFFER; | |
622 | } | |
be077570 | 623 | |
4dc35568 TG |
624 | break; |
625 | } | |
5b34277c TG |
626 | case DHCP_DECLINE: |
627 | log_dhcp_server(server, "DECLINE (0x%x)", | |
628 | be32toh(req->message->xid)); | |
629 | ||
630 | /* TODO: make sure we don't offer this address again */ | |
631 | ||
632 | return 1; | |
633 | ||
634 | break; | |
2dead812 TG |
635 | case DHCP_REQUEST: |
636 | { | |
637 | be32_t address; | |
bd57b450 | 638 | bool init_reboot = false; |
87322b3a | 639 | int pool_offset; |
2dead812 TG |
640 | |
641 | /* see RFC 2131, section 4.3.2 */ | |
642 | ||
643 | if (req->server_id) { | |
644 | log_dhcp_server(server, "REQUEST (selecting) (0x%x)", | |
645 | be32toh(req->message->xid)); | |
646 | ||
647 | /* SELECTING */ | |
648 | if (req->server_id != server->address) | |
649 | /* client did not pick us */ | |
650 | return 0; | |
651 | ||
652 | if (req->message->ciaddr) | |
653 | /* this MUST be zero */ | |
654 | return 0; | |
655 | ||
656 | if (!req->requested_ip) | |
657 | /* this must be filled in with the yiaddr | |
658 | from the chosen OFFER */ | |
659 | return 0; | |
660 | ||
661 | address = req->requested_ip; | |
662 | } else if (req->requested_ip) { | |
663 | log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)", | |
664 | be32toh(req->message->xid)); | |
665 | ||
666 | /* INIT-REBOOT */ | |
667 | if (req->message->ciaddr) | |
668 | /* this MUST be zero */ | |
669 | return 0; | |
670 | ||
bd57b450 | 671 | /* TODO: check more carefully if IP is correct */ |
2dead812 | 672 | address = req->requested_ip; |
bd57b450 | 673 | init_reboot = true; |
2dead812 TG |
674 | } else { |
675 | log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)", | |
676 | be32toh(req->message->xid)); | |
677 | ||
678 | /* REBINDING / RENEWING */ | |
679 | if (!req->message->ciaddr) | |
680 | /* this MUST be filled in with clients IP address */ | |
681 | return 0; | |
682 | ||
683 | address = req->message->ciaddr; | |
684 | } | |
685 | ||
87322b3a TG |
686 | pool_offset = get_pool_offset(server, address); |
687 | ||
688 | /* verify that the requested address is from the pool, and either | |
689 | owned by the current client or free */ | |
690 | if (pool_offset >= 0 && | |
691 | server->bound_leases[pool_offset] == existing_lease) { | |
692 | DHCPLease *lease; | |
693 | usec_t time_now; | |
694 | ||
695 | if (!existing_lease) { | |
696 | lease = new0(DHCPLease, 1); | |
697 | lease->address = req->requested_ip; | |
698 | lease->client_id.data = memdup(req->client_id.data, | |
699 | req->client_id.length); | |
700 | if (!lease->client_id.data) | |
701 | return -ENOMEM; | |
702 | lease->client_id.length = req->client_id.length; | |
703 | } else | |
704 | lease = existing_lease; | |
705 | ||
706 | r = sd_event_now(server->event, CLOCK_MONOTONIC, &time_now); | |
707 | if (r < 0) | |
708 | time_now = now(CLOCK_MONOTONIC); | |
709 | lease->expiration = req->lifetime * USEC_PER_SEC + time_now; | |
710 | ||
2dead812 TG |
711 | r = server_send_ack(server, req, address); |
712 | if (r < 0) { | |
713 | /* this only fails on critical errors */ | |
714 | log_dhcp_server(server, "could not send ack: %s", | |
715 | strerror(-r)); | |
87322b3a TG |
716 | |
717 | if (!existing_lease) | |
718 | dhcp_lease_free(lease); | |
719 | ||
2dead812 TG |
720 | return r; |
721 | } else { | |
722 | log_dhcp_server(server, "ACK (0x%x)", | |
723 | be32toh(req->message->xid)); | |
87322b3a TG |
724 | |
725 | server->bound_leases[pool_offset] = lease; | |
726 | hashmap_put(server->leases_by_client_id, &lease->client_id, lease); | |
727 | ||
2dead812 TG |
728 | return DHCP_ACK; |
729 | } | |
bd57b450 TG |
730 | } else if (init_reboot) { |
731 | r = server_send_nak(server, req); | |
732 | if (r < 0) { | |
733 | /* this only fails on critical errors */ | |
734 | log_dhcp_server(server, "could not send nak: %s", | |
735 | strerror(-r)); | |
736 | return r; | |
737 | } else { | |
738 | log_dhcp_server(server, "NAK (0x%x)", | |
739 | be32toh(req->message->xid)); | |
740 | return DHCP_NAK; | |
741 | } | |
742 | } | |
2dead812 TG |
743 | |
744 | break; | |
745 | } | |
500792d8 TG |
746 | case DHCP_RELEASE: { |
747 | int pool_offset; | |
748 | ||
749 | log_dhcp_server(server, "RELEASE (0x%x)", | |
750 | be32toh(req->message->xid)); | |
751 | ||
752 | if (!existing_lease) | |
753 | return 0; | |
754 | ||
755 | if (existing_lease->address != req->message->ciaddr) | |
756 | return 0; | |
757 | ||
758 | pool_offset = get_pool_offset(server, req->message->ciaddr); | |
759 | if (pool_offset < 0) | |
760 | return 0; | |
761 | ||
762 | if (server->bound_leases[pool_offset] == existing_lease) { | |
763 | server->bound_leases[pool_offset] = NULL; | |
764 | hashmap_remove(server->leases_by_client_id, existing_lease); | |
765 | dhcp_lease_free(existing_lease); | |
766 | ||
767 | return 1; | |
768 | } else | |
769 | return 0; | |
770 | } | |
2dead812 | 771 | } |
4dc35568 TG |
772 | |
773 | return 0; | |
be077570 TG |
774 | } |
775 | ||
ff734080 TG |
776 | static int server_receive_message(sd_event_source *s, int fd, |
777 | uint32_t revents, void *userdata) { | |
be077570 | 778 | _cleanup_free_ DHCPMessage *message = NULL; |
3a864fe4 | 779 | uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))]; |
ff734080 TG |
780 | sd_dhcp_server *server = userdata; |
781 | struct iovec iov = {}; | |
782 | struct msghdr msg = { | |
783 | .msg_iov = &iov, | |
784 | .msg_iovlen = 1, | |
3a864fe4 TG |
785 | .msg_control = cmsgbuf, |
786 | .msg_controllen = sizeof(cmsgbuf), | |
ff734080 | 787 | }; |
3a864fe4 | 788 | struct cmsghdr *cmsg; |
ff734080 TG |
789 | int buflen = 0, len, r; |
790 | ||
791 | assert(server); | |
792 | ||
793 | r = ioctl(fd, FIONREAD, &buflen); | |
794 | if (r < 0) | |
795 | return r; | |
796 | if (buflen < 0) | |
797 | return -EIO; | |
798 | ||
799 | message = malloc0(buflen); | |
800 | if (!message) | |
801 | return -ENOMEM; | |
802 | ||
803 | iov.iov_base = message; | |
804 | iov.iov_len = buflen; | |
805 | ||
806 | len = recvmsg(fd, &msg, 0); | |
807 | if (len < buflen) | |
808 | return 0; | |
be077570 TG |
809 | else if ((size_t)len < sizeof(DHCPMessage)) |
810 | return 0; | |
ff734080 | 811 | |
3a864fe4 TG |
812 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
813 | if (cmsg->cmsg_level == IPPROTO_IP && | |
814 | cmsg->cmsg_type == IP_PKTINFO && | |
815 | cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) { | |
816 | struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg); | |
817 | ||
818 | /* TODO figure out if this can be done as a filter on the socket, like for IPv6 */ | |
819 | if (server->index != info->ipi_ifindex) | |
820 | return 0; | |
821 | ||
822 | break; | |
823 | } | |
824 | } | |
825 | ||
be077570 | 826 | return dhcp_server_handle_message(server, message, (size_t)len); |
ff734080 TG |
827 | } |
828 | ||
829 | int sd_dhcp_server_start(sd_dhcp_server *server) { | |
830 | int r; | |
831 | ||
832 | assert_return(server, -EINVAL); | |
833 | assert_return(server->event, -EINVAL); | |
834 | assert_return(!server->receive_message, -EBUSY); | |
8de4a226 | 835 | assert_return(server->fd_raw == -1, -EBUSY); |
ff734080 | 836 | assert_return(server->fd == -1, -EBUSY); |
20af7091 | 837 | assert_return(server->address != htobe32(INADDR_ANY), -EUNATCH); |
ff734080 | 838 | |
8de4a226 TG |
839 | r = socket(AF_PACKET, SOCK_DGRAM | SOCK_NONBLOCK, 0); |
840 | if (r < 0) { | |
841 | r = -errno; | |
842 | sd_dhcp_server_stop(server); | |
843 | return r; | |
844 | } | |
845 | server->fd_raw = r; | |
846 | ||
ff734080 TG |
847 | r = dhcp_network_bind_udp_socket(INADDR_ANY, DHCP_PORT_SERVER); |
848 | if (r < 0) { | |
849 | sd_dhcp_server_stop(server); | |
850 | return r; | |
851 | } | |
852 | server->fd = r; | |
853 | ||
854 | r = sd_event_add_io(server->event, &server->receive_message, | |
855 | server->fd, EPOLLIN, | |
856 | server_receive_message, server); | |
857 | if (r < 0) { | |
858 | sd_dhcp_server_stop(server); | |
859 | return r; | |
860 | } | |
861 | ||
862 | r = sd_event_source_set_priority(server->receive_message, | |
863 | server->event_priority); | |
864 | if (r < 0) { | |
865 | sd_dhcp_server_stop(server); | |
866 | return r; | |
867 | } | |
868 | ||
869 | log_dhcp_server(server, "STARTED"); | |
870 | ||
871 | return 0; | |
872 | } |